Fuel control assembly



Oct. 6, 1959 c. c. HEBERT ,313

FUEL CONTROL ASSEMBLY Filed Nov. 21, 1956 g dr- D0 mg 5 I m 2 NI C.E.HEBERT INVENTOR 2* BY 57 Law ATTORNEYS United States Patent O FUEL CONTROL ASSEMBLY Clarence C. Hebert, Allen Park, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Application November 21, 1956, Serial No. 623,671

5 Claims. (Cl. 123-140) This invention pertains to a fuel control assembly and more particularly to an assembly adapted for use on motor vehicle fuel control systems for improvement in response time between accelerator demands and fuel administration to the combustion areas.

In many of the fuel supply systems in motor vehicles of today, and especially those systems which depend on a type of supply known as fuel injection, there is a control jector. This, of course, is undesirable as frequently a quick increase in acceleration is desirable not only for operator satisfaction but also for moving the vehicle quickly out of danger situations.

It is, therefore, an object of this invention to provide a uniformly adaptable fuel control system which will practically eliminate the lag in the acceleration cycle in motor vehicle fuel systems particularly of the fuel injection type. It is a further object of this invention to provide such a control system inexpensively and actuated by the intake manifold depression.

Other objects and advantages of this invention will become evident in the following detailed description of one embodiment of this invention which will be understood best when examined with the drawing in which is shown a schematic elevational view of the aforementioned embodiment.

Looking at the drawing is seen control link 21 which at its left end is moved by a control assembly common to fuel injection systems of today. In a conventional system the control link 21 is a fixed length rod connected at one end to a metering control piston or a metering control diaphragm and at its other end to a fuel injector spill valve control arm. Since the exact nature of the control assembly, that is, whether it is a metering control piston or a metering control diaphragm or some other equivalent structure, forms no part of the present invention, the control assembly is merely indicated on the drawing by the reference numeral 33 and is not described in detail.

Similarly, the fuel injector is indicated as a box on the drawing labeled Fuel Injector. The control assembly 33 is usually intake manifold depression sensitive and moves the control link, in the present instance the link 21 in either fuel enrich or fuel lean directions according to the degree of manifold depression. Link 21 is reciprocably mounted in the left end plate of housing 22 with a substantially air tight seal therebetween. Shown in the drawing the right end of link 21 is not attached to piston 23 which is fixed to fuel link 24. Fuel link 24 is reciprocably mounted through the right end of housing 22 and is connected at its right end to a device which varies the amount of fuel injected. Spring 26 is in compression between the right end of housing 22 and piston 23 thereby urging the piston in a leftward direction and into contact with link 21. In this embodiment leftward movement of link 24 results in lean fuel mixture injection to the combustion areas while rightward movement results in an enriching of the fuel mixture as indicated by the arrows. Connection 27 leads to the intake manifold therefore making piston 23 subject to manifold depression at all times. Connection 32 leads from chamber 28 to a vacuum tank 29. Bleed hole 31 is formed in piston 23 and allows the pressures on either side of the piston to gradually be equalized.

The operation of this embodiment is as follows. In normal operation control link 21 abuts piston 23 thereby moving link 24 in a lean or enriched direction depending on the dictates of the control system. Under steady conditions, the pressure in the portion of the chamber 28 to the left of the piston 23, which is also the pressure in connection 27; the pressure in the portion of the chamber 28 to the right of the piston 23; and the pressure in the vacuum tank 29 are all equal to manifold pressure, the pressure being equalized because of the leakage past the piston 23 through the bleed hole 31. When the engine is operating at idle or some steady condition near idle, the pressure in the entire system will be stabilized at a high vacuum. However, on a sharp rise in manifold pressure, such as would be experienced when the throttle is suddenly opened, the vacuum immediately drops in connection 27 and, therefore, in the chamber to the left of piston 23. However, due to the slow rate of leakage past the piston 23 through the bleed hole 31, the vacuum remains high in the portion of chamber 28 to the right of the piston 23 and in the vacuum chamber 29. The pressure differential forces piston 23 to the right against the pressure of spring 26 causing the link 24 to the right in an enriching movement separating piston 23 from control link 21. Gradually, as the manifold depressionis increased and/or the pressure inthe vacuumtank 29 .be-

comes equal to the manifold depression through bleed 31, link 21 will again contact piston 23 causing links 21 and 24 to act in unison. Spring 26 influences the rate of recovery of piston 23 which may be hastened or retarded by changing the spring constant. The time required to return the mechanism to its normal position is dependent on the spring load, spring rate, vacuum chamber capacity and leakage rate past the piston. Without the vacuum tank 29, or some other volumetric enlargement of the portion of chamber 28 to the right of the piston 23, it would be readily apparent that the equalization of the pressure on both sides of the piston would occur so rapidly as to defeat the purpose of the present invention.

Also, upon manifold pressure decrease, as would be the case on vehicle deceleration, the pressure difierential across the piston 23 would cause leftward movement thereof in a fuel cut oil. direction thereby conserving fuel and tending to prevent unburned hydrocarbons from going out of the motor vehicle exhaust.

It will be understood that the invention is not to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined in the appended claims.

Whatis claimed is:

1. In a fuel control system, a device for transmitting movement of a metering control mechanism to a fuel injector mechanism, said transmitting device comprising a cylinder, piston means movable within said cylinder and operatively connected to said fuel injector mechanism, means permitting equalization of pressure within said cylinder on both sides of said piston means, a link member operatively connected to said metering control mechanism, biasing means within said cylinder normally 'urging said'piston means in abutting engagement with said link member whereby said piston means is normally responsive to movement of said link member to operate said fuel injector mechanism, said cylinder having a first port on one side of said piston means connected to a source of intake manifold pressure and a second port on the other side of said piston means connected to a vacuum tank, said piston means being movable in fuel injector mechanism operating direction independently of said link member upon a sudden increase in manifold pressure creating a pressure differential overcoming said biasing means, said equalizing means permitting the pressure on both sides of said piston means to become equalized after a predetermined time interval.

2. In a fuel control system, a device for transmitting movement of a metering control mechanism to a fuel in jector mechanism, said transmitting device comprising a cylinder, piston means movable within said cylinder and operatively connected to said fuel injector mechanism, means permitting equalization of pressure within said cylinder on both sides of said piston means, a link member operatively connected to said metering control mechanism, spring means within said cylinder normally urging said piston means in abutting engagement with said link member whereby said piston means is normally responsive to movement of said link member to operate said fuel injector mechanism, said cylinder having a first port on one side of said piston means connected to a source of intake manifold pressure and a second port on the other side of said piston means connected to a vacuum tank, said piston means being movable in fuel injector mechanism operating direction independently of said link member upon a sudden increase in manifold pressure creating a pressure differential overcoming said spring means, said equalizing means permitting the pressure on both sides of said piston means to become equalized after 'a predetermined time interval, said predetermined time interval being dependent on the spring load, spring rate, vacuum chamber capacity and leakage rate through said aperture.

3. In a fuel control assembly for an engine having operator controlled linkage for increasing the flow of fuel to said engine comprising a cylinder, a fluid pressure responsive member movable within'said cylinder, one side of said member being connected to an engine intake manifold and the other side being connected to a vacuum tank, means for a fluid flow bleed through said member, said member upon sudden manifold pressure increase being caused to move in response thereto in a direction effective to increase the fuel to said engine independently of operator controlled linkage for so doing, said fluid flow bleed means causing said vacuum tank connected side of said fluid pressure responsive member to be brought to intake manifold pressure after a predetermined time delay.

4. In an internal combustion engine fuel metering system a body defining a first pressure portion and a second pressure portion, a movable wall dividing said portions, said first portion in communication with a source of intake manifold pressure, said second portion in communication with a vacuum chamber, pressure bleed means connecting said first portion to said second portion, a fuel injector metering rod connected to said wall for movement therewith, and load-responsive means operable to limit the movement of said wall into said first portion in accordance with engine fuel requirements.

5. A time lag compensator for use with an operator controlled fuel injection system for internal combustion engines comprising a cylinder, a piston reciprocally mounted in said cylinder, a first end of said cylinder connected to a source of intake manifold pressure, the other end connected to a pressure accumulator, means urging said piston toward said first end, fuel injection metering means operably connected to said piston for control of injected fuel quantity upon axial piston movement, selectively positionable means limiting piston movement into said first end and controlled rate pressure equalizing means connecting said accumulator to said first end.

References Cited in the file of this patent FOREIGN PATENTS 

